Device for pre-cooling air in air-cooling units

ABSTRACT

An apparatus for condensing or cooling a heat carrier can be used at power, chemical or oil-refining plants. It comprises a housing, a fan, and a heat exchanger. In front of openings in the housing serving for ambient air intake, at least one water atomizing element is placed connected to an independent water source. The element is a closed contour with nozzles equally spaced along the length of the contour that is rigidly connected to the housing or secured on a base shared with the housing. Preferably, a plurality of water atomizing elements is provided arranged along the perimeter of the housing and connected by a conduit to the water source. Each element is equipped with a shut-off cock to independently service, repair or replace the element. The apparatus improves the interaction of air with the heat carrier and thus enhances the operational efficiency, especially under hot climate conditions.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a continuation-in-part of the International application PCT/RU2016/000073 (publication WO2016/148600) filed Feb. 15, 2016 and claiming priority of the Russian application 2015108829 filed Mar. 13, 2015, the both applications being incorporated herein for reference in their entirety.

BACKGROUND OF THE INVENTION Field of the Invention

The invention relates to air-cooling units (ACU) and can be used for condensing or cooling a heat carrier (coolant) at power, chemical and refinery plants.

Description of the Related Art

Structures of ACU known in the art facilitate, to a degree, the intensification of heat transfer, mainly due to increasing the heat transfer surface through enhancing air or heat carrier distribution inside the ACU. However, as it appears from the related art, the problem of cooling or condensing heat carrier during summer time under hot climate conditions, where ambient temperature goes beyond 30° C., has not been solved. If the heat carrier supplied into an ACU for cooling or condensing is at 30-300° C. and the temperature of the ambient air coming for cooling the heat carrier increases during summer time, the operational efficiency of the ACU decreases.

Known have been ACU made under Russian State Standard P51364-99 “Air cooling apparatus. General specifications” published on 2000 Feb. 8 and in force since 2001 Feb. 1. The ACU is a heat transfer unit, comprising the following main parts: a heat transfer surface (a heat transfer part); a system of air feeding including a fan powered by an electric motor and a diffusor with a collector; and a support structure. Additionally, the ACU can be equipped with an air humidifier required for unloading peak hours in summer time.

This type of ACU suffers from low efficiency of vaporizing water in the stream of air coming into the ACU and, consequently, from a low extent of air cooling. There is provided a pool under the ACU to collect water that did not vaporize in the air. The moisture that did not vaporize finds its way with air at the heat transfer units. Vaporizing from the surfaces of the units, it forms salts thereon. This results in worsening heat transfer and lowering the ACU operational efficiency.

Known from RU2200907 published on 2003 Mar. 20 is an ACU with a water wash system used at elevated temperatures of ambient air, the unit being considered a closest analog. A frame with a metallic mesh and a filtering band is installed between stands and on a bottom plane of an assemblage of heat transfer apparatuses. The metallic mesh is electrically connected with heat transfer tubes, water-jet tubes are directed from the top down and from the center to periphery and are placed on each side in zigzag-shaped rows, an air compressor is connected to the water-jet tubes, and a duct with water is laid around the floor perimeter.

Directing water-jet tubes from the top down and from the center to periphery secures moisturizing the filtering band and the movement of water particles toward the air stream. The filtering band placed on the bottom plane of the assemblage of heat transfer apparatuses catches small particles of water. It is there where water vaporizes on exposure to the air flow.

A problem with this ACU lies in its low efficiency in vaporizing water off the moisturized filtering band in a stream of air coming to the ACU, which results in a low extent of cooling the air. Provided around the ACU perimeter is the duct to collect water that did not vaporize in the air. The filtering band increases resistance to the air coming to the ACU and thus the volume of the air arriving at the ACU decreases. Accordingly, the lesser the air volume, the lower the overall efficiency of the ACU heat transfer. Also, additional spending is required for permanent cleaning of the filtering band.

BRIEF SUMMARY OF THE INVENTION

The object of the invention is enhancing efficiency of ACU under hot climate conditions. The object is achieved through a better interaction of the air and heat carrier.

This better interaction is brought about by providing an apparatus for cooling or condensing a heat carrier, comprising a housing with openings to draw ambient air, a fan, a heat exchanger and at least one water atomizer in front of the openings, the atomizer including a closed contour with nozzles equally spaced along the length of the contour, the atomizer being attached to the housing or attached to a base shared with the housing and being in fluid communication with an independent source of water.

The contour can include two hollow tubes connected together in their upper and bottom portions for the liquid inside thereof to move unidirectionally to thus provide homogeneous pressure between the nozzles.

The diameter of nozzles is preferably between 0.1 and 0.5 mm, the pressure provided in the contour is preferably between 50 and 90 atm.

Preferably, the apparatus comprises a plurality of water atomizers arranged around the perimeter of the apparatus for creating an overcast fog-like curtain and connected to each other by a conduit fed from an independent source of water. Each of the water atomizers is equipped with a shut-off cock to thus allow to independently isolate the atomizer from the conduit and replace it, if need be, without stopping other atomizers.

The design leads to enhancing ACU operating efficiency under hot climate conditions due to forced cooling air arriving at the ACU.

BRIEF DESCRIPTION OF THE DRAWINGS

The above features and advantages of the present invention will now be discussed in more detail with the use of the accompanying drawings, in which:

FIG. 1 presents an isometric view of the apparatus for cooling (condensing) heat carrier according to the invention, with water atomizing elements shown schematically.

FIG. 2 illustrates how water vaporizing elements can be placed around the apparatus.

FIG. 3 shows an element for atomizing water.

DETAILED DESCRIPTION OF THE INVENTION

The apparatus comprises a housing 1 with windows or openings to let air in, a fan 2, and a set 3 of heat exchangers. Arranged externally of the ACU are two hollow tubes connected to each other by their top portions and bottom portions and thus forming a contour constituting a water vaporizing element 4. The tubes can be made, for example, of plastic, stainless steel or brass. The contour is closed and connected to an independent source 6 of water. The tubular portions of the element 4 are equipped with nozzles 7 evenly spaced along the perimeter of the element 4.

In a preferred embodiment, there is a plurality of elements 4 connected to each other by a conduit 5 and forming a closed system around the perimeter of the ACU. Placed in the air intake openings or windows of the housing 1, the elements 4 are on the path of incoming air. They are fed from the water source 6. Each element 4 is provided with a shut-off cock 8 for isolating the element from the system such that repairing or replacing the element can be performed without stopping other elements 4. The nozzle orifice diameter is preferably between 0.1 and 0.5 mm, the pressure provided in the contours is preferably between 50 and 90 atm. Advantageously, the orifice diameter is 0.3 mm, and the pressure of water supplied thereto is 70 atm.

The apparatus operates as follows. The heat carrier to be cooled or condensed is supplied to the heat exchanger 3. Along the conduit 5, water at high pressure is supplied from the independent water source 6 to the elements 4. Through orifices of nozzles 7, water is atomized in an air flow arriving through windows or openings arranged around the housing 1. Upon contact of the hot air flow with the water curtain, the water vaporizes. Since any vaporizing liquid takes energy from its adjacency, the air flow cools. The cooled air flow passes through the fan system 2 and finds its way at the heat exchangers 3 and cools or condenses (depending on the purpose of the apparatus) the heat carrier arriving at the apparatus.

Due to introducing a vaporizing system (element or elements 4) at the air inlet of the ACU, it became feasible to pre-cool the air through vaporizing the moisture that is atomized by nozzles into the air arriving at the ACU. When compared to the closest analog, the present invention makes it possible to separate the process of cooling air from the process of cooling a heat carrier. First, due to creating the fog-like curtain by the nozzles atomizing water upstream the ACU, the highest possible vaporization of micro droplets of water is achieved without having them deposited on the ACU structure. In such a way, the cooling of hot air arriving at the ACU takes place. Then, inside the ACU, in the heat exchanger, through the enhanced heat exchange of the heat carrier with the incoming flow of the air pre-cooled at the entrance of the ACU, the cooling or condensing of the heat carrier occurs. Thus, higher operational efficiency of the ACU, especially under hot climate conditions, is attained. Due to placing the vaporizing elements outside the ACU, the present design makes it possible to access the nozzles atomizing cold water and thus make servicing the ACU simpler. Also, a ring-type vaporizing structure with exterior tubular elements made as rings permits servicing and repairing nozzles of one of the elements with no need for turning off the whole system and stopping the ACU.

The above-discussed array of the tubular atomizing elements of the apparatus makes possible providing homogeneous pressure for each nozzle. If, for example, one element of the spray-type evaporating system is equipped with ten nozzles with orifice diameter of 0.3 mm, the water pressure being 80 atm, 184 liters of water per hour can be evaporated, which results in decreasing the temperature of the air passing through this element by 15° C. The operation of the whole pre-cooling apparatus takes 17 million Kcal per hour, resulting in decreasing the temperature of the air arriving at the ACU by 15° C. on the average. 

1-6. (canceled)
 7. An apparatus for cooling or condensing a heat carrier in an air cooling unit (ACU) comprising a housing with openings to draw incoming air, a fan, and a heat exchanger with the heat carrier, the apparatus comprising, at least, one element for atomizing water and an independent source of water, the element being placed in front of the housing openings, the element including a closed contour with nozzles equally spaced along the length of the contour, the element being in fluid communication with the independent source of water, whereby cooling the incoming air and cooling the heat carrier are separated.
 8. The apparatus of claim 7, wherein the contour of the element includes two hollow tubes connected to each other by upper and bottom portions thereof, whereby liquid can be passed therethrough with homogeneous pressure thereof at each of the nozzles.
 9. The apparatus of claim 7, wherein the element is attached to the housing or to a base shared with the housing.
 10. The apparatus of claim 7, wherein diameter of the nozzles is between 0.1 and 0.5 mm.
 11. The apparatus of claim 7, wherein the pressure between 50 and 90 atm is created in the contour.
 12. The apparatus of claim 7, wherein said at least one element for atomizing water includes a plurality of elements for atomizing water arranged along the perimeter of the ACU, the elements being connected to each other by a conduit fed from the independent source of water, whereby an overcast fog-like curtain is created around the ACU.
 13. The apparatus of claim 12, wherein each element for atomizing water comprises a shut-off cock for independently isolating same from the conduit, whereby each of the elements can be repaired or replaced without stopping other elements.
 14. The apparatus of claim 7, wherein diameter of nozzles is 0.3 mm and the pressure is 70 atm. 